The present invention relates to light bulb sockets and, more particularly, to such a socket which is configured to enable either axial insertion of a bayonet base bulb (straight push), or bayonet insertion thereof (push and twist), along with bayonet removal of the bulb (push, twist, pull).
Many types of automotive lamps employ bayonet based bulbs, such as for tail lights, brake lights, turn signal lights, back-up lights, running lights, and the like. Bayonet type bulbs and sockets are preferred in many automotive applications because positive engagement of electrical contacts can be maintained despite vibrations and jolts experienced by the vehicle frame, as well as temperature variations of the socket components. Additionally, bayonet type bulbs are quick and easy to insert and remove. In contrast, contacts associated with other types of bulb bases can be loosened by such environments. In a typical bayonet arrangement, a bulb has a cylindrical brass barrel or base with at least one and, in automotive applications, usually two projections or pins extending radially therefrom. The base forms one electrical contact, usually the negative contact. An inner end of the base (as installed within a socket) has an electrical contact which is insulated from the base and which is usually designated the positive contact. The base covers a sealed end of an evacuated glass envelope which is otherwise generally spherical and which has a filament mounted therein. The filament is connected between the base and the end contact. A bayonet type socket is typically formed by a sheet metal cylinder with J-shaped slots to receive the pins and an end contact which is resiliently urged in an outward direction. The bulb is inserted axially into the socket until the end contact of the base engages the end contact of the socket and rotated through a small angle to position the base pins in the hooked ends of the J-slots. Removal of a bayonet bulb requires pressing the bulb axially inward against the spring of the end contact, turning through a small angle to release the base pins from the hooked ends of the J-slots, then axial removal of the bulb from the socket. Some types of bayonet style bulbs have a pair of filaments and a corresponding pair of end contacts.
It is generally advantageous, in terms of productivity, to mechanize assembly of manufactured products, as long as the number of manufactured units justify setup costs. While the steps required to insert a bayonet bulb into a bayonet style socket are relatively quick and easy to perform by a human, they are relatively complex to accomplish by mechanical processes. Such a process requires a mechanism to grasp a bulb from a bulb source or carrier, position the bulb in alignment with the socket so that the latch pins of the bulb align with slots in the bayonet socket, insert the bulb base into the socket against the resilient end contact, rotate the bulb to engage the latch pins with the hooked ends of the J-shaped slots, release the bulb, then repeat the process for the next socket to receive a bulb, all without breaking the bulb.
Therefore, there is a need for an improved socket for bayonet style bulbs which simplifies mechanical insertion of bayonet bulbs into such sockets and which enables replacement of the bulb, preferably in a conventional bayonet manner.